Backpack back support frame



FIG. 1 is a front, left side perspective view of a backpack back support frame showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view thereof, the left side elevational view being a mirror image of the right side elevational view;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof. 

CLAIM We claim the ornamental design for a backpack back support frame, as shown and described. 